Grow Tubes Change Microclimate and Bush Architecture but Have Little Effect on Bush Biomass Allocation at the End of the Establishment Year in Blueberry PublicDeposited

To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the American Society for Horticultural Science and can be found at: http://hortsci.ashspublications.org/.

Descriptions

Microclimate variables were integrated over a 6-month period during which
blueberry (Vaccinium corymbosum cv. Liberty) bushes were grown in 51-cm high, 20-cm
diameter round grow tubes (opaque or translucent) on a sawdust mulch-covered raised
bed with the mulch incorporated into tilled soil. Grow tubes were installed around plants
in the spring of 2006, 5 months after planting. Total photosynthetic photon flux (PPF)
density was 55% and 21% of ambient in translucent and opaque tubes, respectively.
Daily maximum vapor pressure deficit consistently was highest in translucent tubes. Air
(T[subscript a]) and stem (T[subscript stem]) temperatures in both grow tube types exceeded T[subscript a] and T[subscript stem] in non-tubed plants (ambient). Maximum mulch surface temperature (T[subscript m]) was lowest in opaque
tubes, whereas there was no difference in T[subscript m] between ambient and translucent tubes. The
soil–mulch interface temperature (T[subscript sm]) was warmer outside tubes than T[subscript sm] inside tubes.
Soil temperatures directly under the tubes differed very little between tube types and
ambient, generally less than 1°C. Root and crown dry mass (DM) did not differ between
tubed plants and ambient at the end of the establishment year. Leaf area, leaf DM, and
fruit bud number were suppressed inside tubes. All plants were greater than 51 cm tall at
the end of the growing season. Substantial compensatory growth occurred above tubes:
tubed plants were more upright and had more leaf area, leaf DM, and shoot growth than
ambient plants above 51 cm. However, there was no difference between tubed and
ambient plants in fruit bud number, total plant leaf area, shoot:root, or DM of 1- and 2-year-old wood. Grow tubes can alter microclimate and architecture of young blueberry
bushes but have no significant influence on size and distribution of total DM after one
growing season in the field.